Question

A point charge Q = 20 nC is located at the origin in the cartesian plane. The charge is surrounded with a medium having relative permittivity of 2.5. The magnitude of electric flux density at point P(1, 2, -2)m is _____pC/$m^2$.(Answer upto 2 decimal places)

• A. 176.83
• B. 17.683
• C. 167.83
• D. 16.783

Answer 1

The correct option is A 176.83

Magnitude of electric flux density,

$|\overrightarrow{D}|=\frac{Q}{4\pi |R{|}^2}$

$R=\sqrt{1^2+2^2+(-2{)}^2}=3m$

$|\overrightarrow{D}|=\frac{20\times {10}^{-9}}{4\pi (3{)}^2}=176.83pC/m^2$